The present invention is directed to electric cigar lighter and power outlet sockets generally, and in particular, such cigar lighter sockets and power outlets that are used in automotive applications.
The invention provides a structure to prevent the occurrence of electrical short circuits in an electrical cigar lighter or electric power outlet socket, commonly found in vehicles, when foreign electrically conductive objects are intentionally or unintentionally placed within the socket and simultaneously touch surfaces that are at different electrical potentials.
FIG. 1 shows a prior art electrical socket for an automobile. The socket might comprise an electrical power outlet for powering portable electrical devices such as computers or charging devices or the electrical socket for a cigar lighter.
As shown in FIG. 1, the outlet comprises a socket well portion 1 and a connector portion 2.
The socket well portion 1 comprises a conductive metal well and the connector portion 2 comprises a plastic insulating member 2A having at least one electrical terminal and generally two terminals 3 and 4, one connected to the vehicle's positive electrical supply and the other connected to the vehicle ground. The metal socket well portion 1 is connected to the electrical terminal generally connected to the vehicle ground.
Typically, the well portion 1 contains an insulating member 5 at the distal end or bottom of the well portion which is riveted to the connector portion 2 by a rivet 6. The rivet 6 is connected to the positive supply terminal and functions as the positive side electrical contact or bears a contact member that engages with a lighter contact or an electrical plug contact that is inserted into the well portion.
When a plug or cigar lighter is inserted into the socket, one contact of the plug engages electrically with the contact rivet 6 or a contact terminal electrically connected to the rivet 6. The other terminal of the plug or cigar lighter electrically engages with the conductive wall of the well portion 1. The assembly shown in FIG. 1 is generally mounted in a mounting ring that is typically made of a plastic material. The mounting ring is inserted into an opening in the panel of the vehicle to hold the power socket or cigar lighter socket in position in the vehicle. The mounting ring may be illuminated and may act as a light transmissive member to aid in locating the socket in a darkened automobile interior.
As shown in FIG. 1, an electrically conducting foreign object, for example, a key 13 or another metallic object, for example, a metallic pen or a metal tool, may intentionally or unintentionally be inserted into the socket. It is then possible to electrically short circuit the socket as shown by the key in FIG. 1 making contact with the positive contact 6 at the same time that it is electrically in contact with the socket well portion 1. This results in a short circuit, typically blowing the vehicle fuse which must be then replaced.
It is an object of the present invention to provide an improved power socket or electrical cigar lighter socket that reduces the possibility of electrical short circuits being created by electrically conductive objects being intentionally or unintentionally inserted into the socket.